The Americans have shown what can be done with their targeted strikes on suspected terrorists in Pakistan and Afghanistan.

But the use of UAVs is controversial, not least because of the way civilians have been killed in some of these missile strikes. Britain has owned up - and apologised for - one of these incidents too.

On the first page of Chapter 1, the document, sets out just how far technology could take UAVs.

"There is a general expectation across defence, academia and industry that unmanned aircraft will become more prevalent, eventually taking over most or all of the tasks currently undertaken by manned systems."

That is a pretty chilling statement for anyone anxious about the power invested in machines.

Another paragraph that caught the eye was on page 39. It begins: "As Stalin allegedly said, "quantity has a quality of its own".

"Modern military aircraft..are now affordable in only small numbers and can take a very long time to bring into service."

Low cost single or dual role unmanned aircraft could be procured in large numbers and used in novel ways.

"In the maritime environment, swarm tactics by small fast boats have proved very effective against surface ships and are difficult to counter.

"Similarly swarms of unmanned aircraft may be used to..overwhelm even modern defence systems."

The document does say that "caution must be applied when considering this approach as practical methods to control swarming systems have yet to be fully developed."